Home How to colour each row so the softest and strongest colour are the minimum and the maximum of each row?

Questions

How to colour each row so the softest and strongest colour are the minimum and the maximum of each row?

June 22, 2023

I made the following graph:

Here’s the code:

    heatmap_branquesCAT <- ggplot(varIPI_branques_CAT_long, aes(x = time, y = branques, fill=values)) +
  geom_tile(aes(width=31)) +
  geom_text(aes(label = round(values, 1)), family="serif", color="black", size=4) +
  scale_x_date(expand=c(0,0), breaks = "1 months", labels=date_format("%b %y")
               # limits = c(as.Date("2023/01/01"), NA)) +
              ) +
  scale_y_discrete(expand=c(0,0), labels=c("Subministrament d'aigua", "Indústries d'alimentació i begudes", "Altres indústries manufactureres", 
                                           "Materials i equips elèctrics, electrònics i òptics", "Energia elèctrica", 
                                           "Fabricació de productes farmacèutics", "Índex general (IPI)", "Indústries extractives",
                                           "Indústries manufactureres", "Fabricació de maquinària i equips mecànics", "Metal·lúrgia i fabricació de productes metàl·lics",
                                           "Fabricació d'altres productes minerals no metàl·lics", "Indústries del paper", "Fabricació productes cautxú i matèries plàstiques",
                                           "Indústries químiques", "Indústries tèxtils",
                                           "Fabricació de material de transport")) +
  labs(title = "Índex de Producció Industrial",
       subtitle = "% de variació interanual",
       x = "", 
       y = " ",
       caption = "Font: Idescat.") +
    scale_fill_gradient2(
      low = "#CC3300",
      mid = "white",
      high = "#66CC00",
   #   midpoint = 0, 
      limits = range(varIPI_branques_CAT_long$values)) +
  guides(color=guide_legend(title="")) +
  theme_minimal() +
  tema +
  theme(axis.text = element_text(size=12, colour = "black"), 
  legend.position="none") 

heatmap_branquesCAT

And a sample of my data:

structure(list(time = structure(c(19083, 19113, 19144, 19174, 
19205, 19236, 19266, 19297, 19327, 19358, 19389, 19417, 19448, 
18993, 19024, 19052, 19083, 19113, 19144, 19174, 19205, 19236, 
19266, 19297, 19327, 19358, 19389, 19417, 19448, 18993, 19024
), class = "Date"), branques = c("Indústries extractives", "Indústries extractives", 
"Indústries extractives", "Indústries extractives", "Indústries extractives", 
"Indústries extractives", "Indústries extractives", "Indústries extractives", 
"Indústries extractives", "Indústries extractives", "Indústries extractives", 
"Indústries extractives", "Indústries extractives", "Indústries manufactureres", 
"Indústries manufactureres", "Indústries manufactureres", "Indústries manufactureres", 
"Indústries manufactureres", "Indústries manufactureres", "Indústries manufactureres", 
"Indústries manufactureres", "Indústries manufactureres", "Indústries manufactureres", 
"Indústries manufactureres", "Indústries manufactureres", "Indústries manufactureres", 
"Indústries manufactureres", "Indústries manufactureres", "Indústries manufactureres", 
"alimentació", "alimentació"), values = c(-17.2, -12, 0.6, 
-6, 8.6, 7.5, 10, 37.1, 26.1, 28.3, 14, 16.8, -9.4, 0.8, 3.1, 
2.5, -2.7, 6.4, 1.9, -2.9, 1.5, 2.5, 0.1, -1.9, -0.1, 5.3, -1.7, 
1.8, -6.8, 4.6, 4.6), scaled_value = structure(c(-0.486164571662395, 
-0.269301398928164, 0.256174750389396, -0.0190746611578974, 0.589810400749752, 
0.543935498825203, 0.648196639562814, 1.77838740515852, 1.31963838591303, 
1.41138818976213, 0.815014464742992, 0.931786942369116, -0.160869812561049, 
0.0939546003127367, 0.338515461609155, 0.274716976053568, -0.278203232094857, 
0.689407132164886, 0.21091849049798, -0.299469393946719, 0.168386166794255, 
0.274716976053568, 0.019523033831218, -0.193138584687407, -0.00174312802064446, 
0.572443241979642, -0.171872422835544, 0.200285409572049, -0.714159550058037, 
0.59745871515621, 0.59745871515621), dim = c(31L, 1L))), row.names = 20:50, class = "data.frame")

So the problem is that now the greens are coloured according to the overall maximum (=50,2). And this gradient should be coloured according to the maximum and minimum of each row.

>Solution :

You need to create a new column where all values are scaled, and base your fill values on that column. (say between 0 and 1, -1 to 1)

For 0-1, something like this:

varIPI_branques_CAT_long <- varIPI_branques_CAT_long |>
  mutate(
    scaled_value = (value - min(value)) / (max(value) - min(value),
    .by = branques
  )

Then replace fill = value with fill = scaled_value in the ggplot code